CANBERRA, Australia – Malaysia's transport minister says an investigation into how a Malaysian airliner came to crash into the Indian Ocean far off course cannot go further until wreckage and its black boxes are found.

Malaysian Transport Minister Liow Tiong Lai is in Australia on Thursday to sign a cost-sharing agreement with the Australian government for the ongoing seabed search for Malaysia Airlines Flight 370.

Liow says investigators have advised that success of the undersea search was crucial to solving the mystery of the disaster. The plane is thought to have crashed 1,800 kilometers (1,100 miles) off Australia's west coast.

The airliner disappeared on March 8 with 239 people aboard during a flight from Kuala Lumpur to Beijing.